Field
The present invention relates generally to the field of image processing and, more particularly, relates generally to a method and apparatus for use in identifying image frames and for comparing video streams.
Related Art
It is desired to identify individual image frames within a video image stream. Typically, timecodes are used to identify frames, wherein each image frame is associated with a corresponding coded time value appropriate to a time position of that image frame within the stream. As an example, the SMPTE timecode standards such as SMPTE 292M or SMPTE 424M are known in the art for commercial broadcast television and motion picture systems. These timecodes are typically used as part of the Serial Digital Interface (SDI) standards for professional broadcast and motion picture systems.
Several difficulties arise with the known timecode frame identification systems. For example, timecodes are not accurately preserved by some types of video editing equipment. The timecodes within one video stream may become unreliable, and mixing together video streams from a plurality of different sources may produce inconsistent timecodes in the combined video stream. The timecodes may become corrupted, and some equipment or transmission systems may even completely remove the timecodes from the video stream.
As another option, it is known to perform watermarking of images frames, i.e. adding a marker element which, typically, is not readily visible to the ordinary viewer. However, watermarking requires editing access to a video stream and intrusively alters the image content by adding the watermark.
It is further desired to accurately identify a given video image stream. In particular, it is desired to determine whether a current video stream has been observed previously or matches with video streams from other sources. However, the known image frame identification systems such as timecodes and watermarking fail to adequately address this difficulty, for the same reasons as noted above.
The example embodiments discussed herein address one or more of these difficulties of the related art. The example embodiments may address other problems as will be appreciated by the skilled person from understanding the teachings herein. In one example, it is desired to provided a method and apparatus for identify image frames within a video stream.